Which hyperparameter does Neural Architecture search (NAS) use?
Great question! It's not clearly stated (it's not stated at all on wikipedia), but after a bit of searching, I found an answer here about a third of the way down the page:


  The best performing architecture observed during the training of the controller is taken, and a grid search is performed over some basic hyperparameters such as learning rate and weight decay in order to achieve near STOTA (state of the art) performance.


So as a direct answer: The norm; A grid search.